elastic-system: Add PodMonitor for exporter

elastic-system/application.yml

@@ -315,3 +315,14 @@ spec:
       beat.k8s.elastic.co/name: filebeat
   podMetricsEndpoints:
     - port: exporter
+---
+apiVersion: monitoring.coreos.com/v1
+kind: PodMonitor
+metadata:
+  name: elasticsearch
+spec:
+  selector:
+    matchLabels:
+      app.kubernetes.io/name: elasticsearch-exporter
+  podMetricsEndpoints:
+    - port: exporter